The present invention concerns an improved ceiling recessed air supply diffuser or air boot. In order to simplify and improve the ceiling appearance, the air diffuser or boot also may be combined with recessed linear fluorescent fixtures, recessed electrical tracks, or other recessed linear devices.
A slot type air diffuser or boot generally comprises an elongated enclosed air chamber having an air inlet collar at a side or on top, and an elongated air outlet throat at the bottom.
In order to be successful and comfortable, an air supply system must deliver air from suitable locations, in appropriate volumes, in proper directions, and at correct velocities.
Any large reductions in volume are not normally made in an air diffuser or boot. Instead, they are made further up-stream to avoid excessive noise generation; but minor reductions, called "trimming" adjustments, are performed in the slot type air diffuser or boot itself and a dampening device must be provided for this purpose. In the prior art the means to reduce the air flow in a traditional slot type air diffuser or boot has been a butterfly damper in the air inlet collar or a hinged full-length damper in the air outlet throat.
Except in very high-ceilinged spaces, the proper direction for air emitted from the air boot is always in a tight horizontal pattern closely hugging the ceiling. In a recessed linear slot type air supply device the primary means for effecting such a horizontal pattern is always a projection, at the bottom of the throat and approximately in the plane of the ceiling under-surface, which deflects the air across the ceiling. The air in the throat must first be directed toward this projection and traditionally this has been accomplished by a flat or curved blade within the throat and equal to it in length. Often this blade has also been hinged to also serve as a volume control or damper.
All of these traditional means for trimming air volume and directing air flow have had the severe disadvantage that they use elements that hinder and disrupt the air flow. This happens especially when the slot type air diffuser or boot is operating near its maximum volume levels as established by pressure and noise criteria, since these elements always remain within the air path and severely limit the air diffuser or boot performance.
Another disadvantage of the traditional slot type air diffuser or boot occurs at reduced volume levels of performance. With reduced volume the pressure and velocity is also decreased, and the air diffuser or boot is incapable of projecting the emitted air to any great distance across the ceiling. Because high supply velocities at the outlet are necessary to maximize room air induction, the process by which the air stream induces movement into a much larger air mass, this may result in failure of air coverage in the conditioned space.
The traditional slot type air diffuser or boot used alongside a recessed fluorescent fixture is mounted directly on and is fully supported by the fixture. Such an air boot has its entire throat engaged in a socket portion of the fixture which runs the full length of the fixture, and the boot is stabilized by a bracket attached between it and the top of the fixture. Consequently, the air boot cannot be installed in the ceiling until after the light fixture has been installed, which is highly undesirable for building scheduling flexibility.